arXiv subjects

Carsten Detlefs

Publications and source records attributed to Carsten Detlefs.

At least 19 recordsLinked to original sources

arXiv2026

A surviving pink spinel records an early aluminous melt on the ureilite parent body

Ureilites are ultramafic achondrites interpreted as fragments of a differentiated parent body, yet their origin and evolution remain debated because textural equilibrium coexists with chemically primitive compositions. Here we report mineralogical, isotopic, and microstructural observations from polymict ureilite Elephant Moraine (EET) 87720. The sample contains unusually magnesian olivine (Mg# up to 98.7), Ca-poor pyroxene (Wo as low as 1.0), and rare coarse-grained pink aluminous spinel containing 56.4-58.7 wt% Al2O3 and 11.3-11.8 wt% Cr2O3. In situ triple oxygen isotope measurements of spinel and associated forsteritic olivine plot along the ~1-slope Carbonaceous Chondrite Anhydrous Mineral (CCAM) line, consistent with bulk ureilites. The clasts also follow the ureilitic Fe-loss/addition trend, with near-constant chondritic Mn/Mg ratios. These observations demonstrate that the clasts are indigenous to the ureilite parent body and extend the known ureilite oxygen isotope range to delta18O ~9.7 per mil. Three-dimensional dark-field X-ray microscopy reveals a hierarchical deformation microstructure in the spinel, comprising distributed lattice curvature, localized slip-band-like boundaries, and coherent mosaic-domain boundaries, indicating multiscale accommodation of shock-induced crystal-plastic deformation. We propose that the aluminous spinel crystallized from a locally Al-rich, Ca-poor melt under low oxygen fugacity. Al partitioning between coexisting spinel and olivine yields a crystallization temperature of 1318 +/- 43 K, consistent with a thermally elevated parent body. The spinel may therefore preserve a rare crystallization product of an early aluminous melt that has largely disappeared from the ureilite record, providing an archive of early planetary differentiation.

astro-ph.EP↗

arXiv2026

Automated Burgers Vector Identification for Individual Dislocations in Bulk Crystals

Weak-beam imaging in dark-field X-ray microscopy (DFXM) can resolve individual dislocations in bulk crystals, but assigning Burgers vectors from the resulting contrast typically requires manual comparison with forward simulations. Here, we train a physics-informed convolutional neural network (CNN) on geometrical optics simulations of isolated dislocations in face-centred cubic (FCC) aluminium, incorporating crystallographic constraints into the learning pro- cess. The model identifies Burgers vectors from weak-beam integrated rocking-curve images. On synthetic test data, the model achieves an accuracy of approximately 93%. In an experimental cross-slip case, the constrained model as- signs 72.7% of the layer-wise predictions to the reference Burgers vector. These results show that simulation-trained, physics-informed CNNs represent a step toward automated dislocation identification in DFXM.

cond-mat.mtrl-sci↗

arXiv2026

Subgrain-resolved Analysis of Degradation in Cu Metallization via Scanning 3DXRD and Thermomechanical Modeling

Metallization layers play a key role in the performance and reliability of modern power semiconductor devices. During short-circuit events, rapid heating of power metallization layers induces thermomechanical incompatibility stresses, which may contribute to material degradation and impact device performance. In this work, potential degradation hotspots associated with thermomechanical loading in Cu power metallization are investigated using a combined experimental--computational approach. Scanning three-dimensional X-ray diffraction measurements are coupled with thermomechanical crystal plasticity simulations to probe the evolution of grain-resolved plastic deformation during rapid cyclic loading. This integrated approach provides insight into the microstructural processes governing degradation hotspot formation, laying the groundwork for future microstructure-informed, physics-based reliability assessment of Cu metallization.

cond-mat.mtrl-sci↗

arXiv2026

Diamond compound refractive lenses for high energy Dark Field X-ray Microscopy

Compound-refractive lenses (CRL) are a type of x-ray optics that find widespread applications as focusing and imaging lenses. The choice of material is one of the most defining properties of these lenses. In this work, we present a CRL made out of diamond. It provides an advantageous balance between refractivity and absorption, along with good manufacturability. Compared to Be CRLs, it features a higher optical density and thus enables application at higher photon energies without relying on large lens stacks or very small radii of curvature, which are challenging to manufacture. A diamond CRL is characterized for use as an objective for Dark-field X-ray Microscopy (DFXM) at the ID03 beamline of the European Synchrotron Radiation Facility (ESRF) and compared to Al and Be CRLs at 17 keV, 33 keV and 37 keV. Increasing the photon energy in DFXM from 17 keV to 37 keV opens up the possibility to investigate new sample systems, that were previously opaque to low energy x-ray radiation. The capability of the diamond CRL at 33 keV is illustrated through DFXM measurements on two 0.5 mm-thick iron-based samples, which cannot be probed at 17 keV.

cond-mat.mtrl-sci↗

arXiv2026

Multilayer Laue Lenses for Enhanced Spatial Resolution in Dark-Field X-ray Microscopy

We introduce the use of a crossed pair of Multilayer Laue Lenses (MLLs) as an objective in Dark-Field X-ray Microscopy (DFXM). In a demonstration experiment at the ID03 beamline at ESRF, two flat Mo-Si MLLs were used, with a physical aperture of 50 x 50 $\mathrm{\mu m^2}$ and a focal length of 14.25 mm at 19 keV. Applying a 10 % criterion to the Modulation Transfer Functions (MTFs) acquired, a spatial resolution of 56 nm is obtained in bright-field mode -- more than three times better than with a compound refractive lens (CRL) objective. The dark-field resolution is similar. With an efficiency of 26.7 % the MLL objective expands the science domain of DFXM significantly, both for bulk and near-surface studies. Similar to the CRL case, the reciprocal space resolution is dominated by the numerical aperture (NA) of the objective, with the NA being three times larger in the MLL case. This enables faster orientation mapping and implies improved options for the use of tomographic reconstruction algorithms. Although the MLL objective pupil varies with energy and position, secondary peaks are suppressed, simplifying both interpretation and forward simulations. We present an example DFXM application using the MLL as an objective, imaging a through-silicon via Kelvin device.

cond-mat.mtrl-sci↗

arXiv2026

Revealing 3D orientation and strain heterogeneity in calcite generated by bio-cementation

Bio-cementation uses bacterially induced calcite to bind sand grains, offering a low-carbon approach to soil stabilization. However, the 3D morphology, orientation texture, and internal strain states of individual calcite bonds remain insufficiently characterized. Here, we combine computed micro-tomography, 3D X-ray Diffraction (3DXRD), and Dark-Field X-ray Microscopy (DFXM) to nondestructively characterize grain morphology, crystallographic orientation, and both type II (intergranular) and type III (intragranular) elastic strains in calcite formed at sand-sand contacts during bio-cementation. Tomography establishes the sample morphology and the cemented contact architecture; 3DXRD provides grain-averaged orientation and strain states; and DFXM resolves sub-grain misorientations and localized strain concentrations generated during growth with 100 nm resolution. The combined results show that calcite precipitation through bio-cementation produces anisotropic internal strain and distinct sub-domain structures that can influence bond integrity and load transfer at the macroscopic scale.

cond-mat.mtrl-sci↗

arXiv2026

Unexpected Planar Dislocation Boundary Formation in FCC Metals Captured by Dark-Field X-ray Microscopy and Continuum Dislocation Dynamics

Validating dislocation patterning models against in situ imaging experiments is a longstanding goal in materials physics. Here, we provide the first direct morphological comparison of such models. Using in situ Dark-Field X-ray Microscopy (DFXM), we map the local orientations in high-purity aluminium deformed along [100] and find unexpected planar dislocation boundaries aligned with {111} slip planes that form prior to the development of a conventional dislocation cell structure. To explain this behaviour, we generate synthetic DFXM contrast images from a continuum dislocation dynamics (CDD) simulation. This mesoscale model, using nickel as a high stacking fault energy (SFE) FCC analogue, independently predicts the formation of the same {111} planar boundary types. This correspondence demonstrates that state-of-the-art CDD and DFXM experimental data can be used synergistically - despite differences in strain rates and length scales - as a practical route for refining continuum theories of plasticity.

cond-mat.mtrl-sci↗

arXiv2025

Remanent crustal strain on Mars in non-poikilitic olivine of NWA 7721

We present a multiscale microstructural analysis of olivine from the non-poikilitic lithology of the poikilitic shergottite NWA 7721, using dark-field X-ray microscopy (DFXM), electron backscatter diffraction (EBSD), and context in situ 2D micro-XRD. A single olivine crystal contains two distinct subgrain populations. Type 1 subgrains are fine (1-5 micrometers), randomly oriented, and nearly strain-free, whereas Type 2 subgrains are coarse (greater than 30 micrometers), aligned, and strongly strained. Layered DFXM data reveal slip-band features in Type 2 that are absent in Type 1. We interpret Type 1 as products of shock-induced recrystallization, whereas Type 2 preserves remnants of a highly deformed parent grain. This bimodal microstructure, not observed in other Martian meteorites including the paired NWA 1950 and ALH A77005, points to a heterogeneous response to impact influenced by pre-existing strain in the olivine grain. We propose that NWA 7721 olivine experienced substantial crustal or magmatic stress before impact. The subsequent shock wave imposed a rapid load-release cycle that mobilized dislocations and produced low-angle boundaries in Type 2, while driving recrystallization of Type 1. Grain-growth constraints limit the post-shock heating duration to approximately 2.3 s, consistent with rapid quenching. These results provide the first evidence that non-poikilitic olivine in NWA 7721 preserves dynamic crustal deformation on Mars in the Late Amazonian.

astro-ph.EP↗

arXiv2025

Quantifying Resolution in Pink Beam Dark Field X-ray Microscopy: Experiments and Simulations

Pink-beam Dark-Field X-ray Microscopy (pDFXM) is a powerful emerging technique for time-resolved studies of microstructure and strain evolution in bulk crystalline materials. In this work, we systematically assess the performance of pDFXM relative to monochromatic DFXM when using a compound refractive lens (CRL) as the objective. Analytical expressions for the spatial and angular resolution are derived and compared with numerical simulations based on geometrical optics and experimental data. The pink-beam configuration provides an increased diffraction intensity depending on the deformation state of the sample, accompanied by a general tenfold degradation in angular resolution along the rocking and longitudinal directions. This trade-off is disadvantageous for axial strain mapping, but can be advantageous in cases where integrated intensities are needed. For a perfect crystal under parallel illumination with a pink beam, our results show that chromatic aberration is absent, whereas under condensed illumination it becomes significant. The aberration is shown to depend strongly on the local distortion of the crystal. Weak-beam imaging conditions, such as those required for resolving dislocations, are shown to remain feasible under pink-beam operation and may even provide an improved signal-to-noise ratio. The higher incident flux, enhanced by nearly two orders of magnitude, is quantified in terms of beam heating effects, and implications for optimized scanning protocols are discussed.

physics.optics↗

arXiv2025

Bridging Grain Mapping and Dark Field X-ray Microscopy for Multiscale Diffraction Imaging

Resolving how defects emerge and interact within the hierarchical structure of polycrystalline materials remains a core challenge in materials science. Grain-mapping methods such as three-dimensional X-ray diffraction (3DXRD) and diffraction contrast tomography (DCT) provide essential mesoscale context but lack the resolution to image lattice defects. Conversely, high-resolution methods like Dark Field X-ray Microscopy (DFXM) capture lattice distortions but not the surrounding microstructure. Here, we introduce a transferable framework that unifies these complementary approaches into a single, non-destructive workflow. Enabled by open-source software, the method translates grain orientation and position data into precise goniometer settings for DFXM imaging without dismounting or reorienting the sample. Applied to an iron polycrystal containing 1100 grains, DFXM motor positions were calculated for all grains within seconds, enabling on-the-fly targeting of specific grains. This allows reproducible zooming from the millimetre-scale aggregate to individual dislocations. We resolve three-dimensional misorientation fields across grain boundaries with 36 nm pixel size, directly capturing grain-grain interactions within their microstructural context. Finally, we show transferability from LabDCT to synchrotron and XFEL platforms, enabling new ways of studying defect interactions across scales.

physics.app-ph↗

arXiv2025

Computation and Sensitivity Analysis of the Deformation-Gradient Tensor Reconstruction in Dark-Field X-ray Microscopy

Spatially resolved strain measurements are crucial to understanding the properties of engineering materials. Although strain measurements utilizing techniques such as transmission electron microscopy and electron backscatter diffraction offer high spatial resolution, they are limited to surface or thin samples. X-ray diffraction methods, including Bragg Coherent Diffraction Imaging and X-ray topography, enable strain measurements deep inside bulk materials but face challenges in simultaneously achieving both high spatial resolution and large field-of-view. Dark-field X-ray Microscopy (DFXM) offers a promising solution with its ability to image bulk crystals at the nanoscale while offering a field-of-view approaching a few hundred $\mu$m. However, an inverse modeling framework to explicitly relate the angular shifts in DFXM to the strain and lattice rotation tensors is lacking. In this paper, we develop such an inverse modeling formalism. Using the oblique diffraction geometry, enabling access to noncoplanar symmetry-equivalent reflections, we demonstrate that the reconstruction of the full deformation gradient tensor ($\mathbf{F^{(g)}}$) is possible. We also develop the computational framework to both forward calculate the anticipated angular shifts and reconstruct the average $\mathbf{F^{(g)}}$ for an individual pixel from DFXM experiments. Finally, utilizing the established formalism and computational framework, we present methods for sensitivity analysis to relate individual components of the rotation or strain tensor to specific angles of DFXM. The developed sensitivity analysis also enables explicit computation of the errors associated with the reconstruction of each component. The formalism, the computational framework, and the sensitivity analysis established in this paper should assist both the interpretation of past DFXM experiments and the design of future DFXM experiments.

cond-mat.mtrl-sci↗

arXiv2025

A high-temperature furnace for multi-modal synchrotron-based X-ray microscopy and diffraction imaging

The design, calibration, and initial application of a non-contact high-temperature furnace developed for in situ synchrotron X-ray experiments are presented. The system enables a stable operation up to 1000 {\deg}C, with heating rates exceeding 6000 {\deg}C/min and thermal stability better than {\pm}2 {\deg}C. Temperature calibration was performed using (i) direct measurements with a thermocouple to characterize heating and cooling ramp rates and map temperature gradients along the x, y, and z axes, and (ii) synchrotron X-ray diffraction to track the ferrite-to-austenite (BCC to FCC) phase transition in an iron grain under beamline conditions. The furnace's contactless geometry provides full translational and rotational freedom, with 360{\deg} rotation and wide tilt capabilities, making it fully compatible with a range of diffraction and imaging techniques. Its 3D-printed modular body includes closable apertures for auxiliary functions such as active cooling or X-ray fluorescence. The design is easily customizable for diverse experimental requirements and can be adapted to most beamlines. The furnace has been implemented at the ID03 beamline of the European Synchrotron Radiation Facility (ESRF) which supports Dark field X-ray Microscopy (DFXM), 3D X-ray Diffraction (3DXRD), magnified topotomography (MTT), phase-contrast tomography (PCT) and diffraction contrast tomography (DCT). As a first application, a DFXM case study on a cold-rolled Al1050 sample during isothermal annealing is presented. The imaging of a selected grain before and after the heat treatment reveals strain relaxation and grain growth. This furnace offers a robust and flexible platform for high-temperature synchrotron studies across materials science, including metals, ceramics, and energy materials. It is now part of the ESRF sample environment pool and is available to all users.

physics.ins-det↗

arXiv2025

Pink-Beam Dark Field X-ray Microscopy: Expanding 3D/4D Imaging for Complex and Deformed Microstructures

Dark Field X-ray Microscopy (DFXM) has advanced 3D non-destructive, high-resolution imaging of strain and orientation in crystalline materials, enabling the study of embedded structures in bulk. However, the photon-intensive nature of monochromatic DFXM limits its applicability to highly deformed or weakly crystalline structures and constrains time-resolved studies in industrially relevant materials. We present pink-beam DFXM (\pDFXM) at the ID03 beamline of ESRF, achieving a 27-fold increase in diffracted intensity while maintaining 100 nm spatial resolution. We validate \pDFXM{} by imaging a partially recrystallized aluminum grain, confirming sufficient angular resolution for microstructure mapping. The increased flux significantly enhances the diffracted signal, enabling the resolution of subgrain structures. Additionally, we image a highly deformed ferritic iron grain, previously inaccessible in monochromatic mode without focusing optics. Beyond static imaging, \pDFXM{} enables real-time tracking of grain growth during annealing, achieving hundred-millisecond temporal resolution. By combining high photon flux with non-destructive, high-resolution 3D mapping, \pDFXM{} expands diffraction-contrast imaging to poorly diffracting crystals, unlocking new opportunities for studying grain growth, fatigue, and corrosion in bulk materials.

physics.app-ph↗

arXiv2024

Three-dimensional nucleation and growth of deformation twins in magnesium

At two-thirds the weight of aluminum, magnesium alloys have the potential to significantly reduce the fuel consumption of transportation vehicles. These advancements depend on our ability to optimize the desirable versus undesirable effects of deformation twins: three dimensional (3D) microstructural domains that form under mechanical stresses. Previously only characterized using surface or thin-film measurements, here, we present the first 3D in-situ characterization of deformation twinning inside an embedded grain over mesoscopic fields of view using dark-field X-ray microscopy supported by crystal plasticity finite element analysis. The results reveal the important role of triple junctions on twin nucleation, that twin growth behavior is irregular and can occur in several directions simultaneously, and that twin-grain and twin-twin junctions are the sites of localized dislocation accumulation, a necessary precursor to crack initiation.

cond-mat.mtrl-sci↗

arXiv2024

Observing formation and evolution of dislocation cells during plastic deformation

During plastic deformation of metals and alloys, dislocations self-organise in cells, which subsequently continuously decrease in size. How and when these processes take place has remained elusive, because observations of the structural dynamics in the bulk have not been feasible. We here present X-ray diffraction microscopy movies of the structural evolution during tensile deformation of a mm-sized aluminium (111) single crystal. The formation and subsequent development of 40,000 cells are visualised. We reveal that cells form in a stochastic and isotropic manner already at 1% strain. We show that the cell size and dislocation density distributions are log-normal and bi-modal Gaussian distributions, respectively, throughout. This insight leads to an interpretation of the formation and evolution steps in terms of universal stochastic multiplicative processes. This work will guide dislocation dynamics modelling, as it provides unique results on cell formation.

cond-mat.mtrl-sci↗

arXiv2024

Spatially resolved mapping of coherent twin relationships in DFXM measurements

With dark firld x-ray microscopy, it is possible to measure reciprocal space manps of localized volumes embedded deeply in a large sample. Ferroelastic materials contains elastic twins that display characteristing splitting of diffraction peaks. We show how to utilize established methods for analysing reciprocal space maps of elastically twinned materials to the analysis of dark-field x-ray microscopy data to detemin the exact kind of domain wall present in each probed volume, even when the domains are not spatially resolved.

cond-mat.mtrl-sci↗

arXiv2023

3D Microstructural and Strain Evolution During the Early Stages of Tensile Deformation

Dislocation patterning and self-organization during plastic deformation are associated with work hardening, but the exact mechanisms remain elusive. This is partly because studies of the structure and local strain during the initial stages of plastic deformation has been a challenge. Here we use Dark Field X-ray Microscopy to generate 3D maps of embedded $350 \times 900 \times 72 \,μ\mathrm{m}^3$ volumes within three pure Al single crystals, all oriented for double slip on the primary and conjugate slip systems. These were tensile deformed by 0.6$\%$, 1.7$\%$ and 3.6$\%$, respectively. Orientation maps revealed the existence of two distinct types of planar dislocation boundaries both at 0.6$\%$ and 1.7$\%$ but no systematic patterning. At 3.6$\%$, these boundaries have evolved into a well-defined checkerboard pattern, characteristic of Geometrically Necessary Boundaries, GNBs. The GNB spacing is $\approx$ 14 $μ$m and the misorientation $\approx$ 0.2°, in fair agreement with those at higher strains. By contrast to the sharp boundaries observed at higher strains, the boundaries are associated with a sinusoidal orientation gradient. Maps of the elastic strain along the (111) direction exhibit fluctuations of $\pm 0.0002 $ with an average domain size of 3 $μ$m.

cond-mat.mtrl-sci↗

arXiv2022

Tilting refractive x-ray lenses for fine-tuning their focal length

In this work, we measure and model tilted x-ray refractive lenses to investigate their effects on an x-ray beam. The modelling is benchmarked against at-wavelength metrology obtained with x-ray speckle vector tracking experiments (XSVT) at the BM05 beamline at the ESRF-EBS light source, showing very good agreement. This validation permits us to explore possible applications of tilted x-ray lenses in optical design: we demonstrate that tilting 1D lenses around their focusing direction can be used for fine-tuning their focal length with possible applications in beamline optical design.

physics.optics↗